SAP What is # 6 - What is "FX" Lot size ?

First of all, "FX" means Fixed Lot-sizing rule which is a type of Static Lot-Sizing rule which you assign to the MRP 1 view of the material master.

You assign the "FX" lot size rule in the MRP 1 view as below:
"FX" and 100 as the fixed lot size.

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Assuming you have the demand reservations of 1100 and current stock situation of 1000 as below

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As BELOW, the MRP result creates 2 supplies of 100 each according to the "FX" with 100 as the fixed lot size from the MPR view 1.

NOTICE that Both the Supplies are on the SAME DATE.

From SAP的学习和考试 Learning & Examination

CONLUSION: "FX" or fixed lot size rule is a basic static lot size rule. A fixed lot size quantity is mandatory when you assign a Fixed Lot size key in the MRP 1 view in the material master. MRP run creates multiples of the fixed lot size quantity with a separate supply MRP element.

APPLICATION: Useful when either the supplier or buyer impose a packing requirement as well as unique traceability of a standard lot size. I find that some organizations also apply this to each truck load as an order.
For example, buying 10 tons of sand with each ton per truck and therefore each ton is one PO or PO line item and one goods receipt which will then allow for unique tracking of the truck delivery. Therefore, the 10 tons will result in 10 supply MRP element each of 1 ton. Ultimately a single PO with 10 line items.

CAUTION: Need to consider real requirements not just from the perspective of planning but also goods receipt, storage, and amount of work needed to administer multiple supply elements.
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